<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<!--
   js中的常见数据类型
    1. number  数值
    2. string  字符串
    3. boolean   布尔型  true  false
    4. object     对象类型
    5. function     函数
    6. undefined     undefined
-->


<script>
  var info;
  console.log("info:",info)

  var number = 1

  console.log("typeof 1 : ",typeof number)
  var str = "hello"

  console.log("typeof hello :",typeof str)
  var bln = true

  console.log("typeof true :",typeof bln)
  var  un;
  console.log("un:",un)

  console.log(typeof  un)
  var obj1 = {
     stuNo:'20241230001',
     stuName:'lisi'
  }
  console.log("obj1:",obj1)

  console.log(typeof  obj1)
  var obj2 = new Object()
  obj2.stuNo = '20241230001'
  obj2.stuName = 'lisi'
  console.log("obj2:",obj2)


  console.log(typeof  obj2)

  // 变量提升过程
  info = "hello"

  // 函数类型     实现代码封装   提升代码复用

 //  参数列表      函数中封装的代码不会自动执行   调用函数
  function  fn (num1 ,num2){
      var  result = num1 + num2
      result = result * 10
      result = result -5
      return   result;
  }

  // 调用函数
   var  res =  fn(1,2)
  console.log(res)



</script>


</body>
</html>